Triangular Number Calculator

Find the nth triangular number.

Triangular number 55

Formula: Tₙ = n(n + 1) ÷ 2

Step-by-step with your numbers:

1. Values used:

2. n = 10

4. Triangular number = 55

Did we solve your problem today?

Triangular numbers count dots forming a triangle (1, 3, 6, 10, …).

The math behind it

Tₙ = n(n+1) ÷ 2 — also the sum of the first n whole numbers.

T₁₀ = 10×11÷2 = 55.

Use?

Sums of consecutive numbers and handshake problems.